Updated the changelog

CHANGELOG.md

@@ -1,10 +1,12 @@
 ## vNext (TBD)
 
+### Notes
+Based on Realm JS v10.21.1: See changelog below for details on enhancements and fixes introduced between this and the previous pre release (which was based on Realm JS v10.19.5).
+
 ### Enhancements
 * Small improvement to performance by caching JSI property String object [#4863](https://github.com/realm/realm-js/pull/4863)
 
 ### Fixed
-* <How to hit and notice issue? what was the impact?> ([#????](https://github.com/realm/realm-js/issues/????), since v?.?.?)
 * None
 
 ### Compatibility
@@ -25,17 +27,11 @@
 * Fixed pinning of the NDK used to build our prebuilt binaries for Android. Our previous version, Realm JS v10.21.0 was compiled with NDK 25.1.8937393, which could result in unpredictable crashes, since this needs to match the one being used by React Native. ((#4910)[https://github.com/realm/realm-js/pull/4910], since v10.21.0)
 
 ### Compatibility
-* React Native >= v0.64.0
+* React Native >= v0.70.0
 * Atlas App Services.
 * Realm Studio v12.0.0.
-* APIs are backwards compatible with all previous releases of Realm JavaScript in the 10.5.x series.
 * File format: generates Realms with format v22 (reads and upgrades file format v5 or later for non-synced Realm, upgrades file format v10 or later for synced Realms).
 
-### Internal
-<!-- * Either mention core version or upgrade -->
-<!-- * Using Realm Core vX.Y.Z -->
-<!-- * Upgraded Realm Core from vX.Y.Z to vA.B.C -->
-
 ## 10.21.0 (2022-09-09)
 
 ### Enhancements